Re: Database and Table stats gets reset automatically

On Mon, 25 Jul 2016, 10:35 p.m. Adrian Klaver, <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> On 07/25/2016 07:28 AM, Sameer Kumar wrote:
> >
> >
> > On Mon, 25 Jul 2016, 10:10 p.m. Adrian Klaver,
> > <adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>> wrote:
> >
> > On 07/24/2016 09:58 PM, Sameer Kumar wrote:
> > > Hi,
> > >
> > > I have PostgreSQL v9.4.4 running in my environment. It has been up
> for
> > > over 2 years now. I noticed that suddenly the statistics have been
> > reset
> > > and all the stat tables/columns got restarted from.
> >
> > Any of these happen?:
> >
> > https://www.postgresql.org/docs/9.4/static/monitoring-stats.html
> > ". When recovery is performed at server start (e.g. after immediate
> > shutdown, server crash, and point-in-time recovery), all statistics
> > counters are reset."
> >
> >
> >
> > Nope. This has happened on the standby database. The counter on the
> > master database are still running fine.
> >
> > There was a period of few days about a month ago when I had to reverse
> > the roles but then I switched them back to the way they were. But
> > recently, I have not done anything which brings the server out of
> recovery.
> >
> >
> > >
> > > This happened 2 weeks ago. I noticed only recently after I looked
> > at the
> > > plot over last week (which dipped suddenly for "number of tuples
> > > returned", "number of conflicts" etc).
> >
> > Any change in procedures the last two weeks?
> >
> >
> > Nope. The scripts to capture this data to csv file is very much the same.
> >
> >
> > >
> > > The columns which got reset are from pg_stat_database,
> > > pg_stat_user_tables, pg_stat_bgwriter
> > >
> > > As far I know no one has fired pg_stat_reset or
> pg_stat_reset_shared.
> > >
> > > I noticed that the last largest value is from pg_stat_user_tables.
> > > tup_returned (470440261405). Does the statistics get reset
> > automatically
> >
> > tup_returned is in pg_stat_database.
> >
> >
> > Sorry my bad (a copy paste mistake). Yes I was referring to tup_returned
> > from pg_stat_database. But the various stats in pg_stat_user_tables have
> > also been reset.
> >
> >
> > What does the stats_reset field show in pg_stat_database?
> >
> >
> > It says a timestamp from 18th July 2016. Infact all the other statistics
> > views have the same timestamp.
>
> Don't suppose you still have the logs from that date to see if there is
> a clue?
>

I don't have them on the server. I can fetch them from the archives. Ot
might tke a day or two. Let me get back. Thanks for helping.
Any idea about probable suspects apart from the ones you listed?

> >
> >
> > > when the value for one of the statistics reaches the high number
> > > supported by int4?
> > >
> > > I am running on Red Hat 6.7.
> > >
> > > Regards
> > > Sameer
> > > --
> > > --
> > > Best Regards
> > > Sameer Kumar | DB Solution Architect
> > > *ASHNIK PTE. LTD.*
> > >
> > > 101 Cecil Street, #11-11 Tong Eng Building, Singapore 069 533
> > >
> > > T: +65 6438 3504 | M: +65 8110 0350 | www.ashnik.com
> > <http://www.ashnik.com>
> > >
> >
> >
> > --
> > Adrian Klaver
> > adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>
> >
> > --
> > --
> > Best Regards
> > Sameer Kumar | DB Solution Architect
> > *ASHNIK PTE. LTD.*
> >
> > 101 Cecil Street, #11-11 Tong Eng Building, Singapore 069 533
> >
> > T: +65 6438 3504 | M: +65 8110 0350 | www.ashnik.com
> >
>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com
>
--
--
Best Regards
Sameer Kumar | DB Solution Architect
*ASHNIK PTE. LTD.*

101 Cecil Street, #11-11 Tong Eng Building, Singapore 069 533

T: +65 6438 3504 | M: +65 8110 0350 | www.ashnik.com